It is a known problem in electrical systems to make reliable electrical connections between contact terminals in mated electrical connectors. Generally, an electrical connection is established by creating a contact force between the contact terminals. A strong contact force helps to reduce oxidation of the contact terminals and maintains the connection when the terminals are subjected to vibration or shock. Without a strong contact force, the electrical connection may disengage over time through creep of the contact terminals.
It is also a problem to make electrical connections which may be disconnected and reconnected easily without damage to the connectors. Strong contact forces result in high insertion forces when mating multi-terminal connectors, making the connection difficult to achieve and often damaging the contact terminals during repetitive connection and disconnection processes.
One device used to create the contact force in electrical connectors is to make the contact terminals in the form of cantilever beam springs which are deflected when the connectors are mated together. In electrical connectors of the cantilever beam spring type that have a large number of terminals, the cumulative insertion force can be relatively high. Reducing the contact force at the individual terminals effectively reduces the insertion force but results in a poor electrical connection. Also, the increasing need to miniaturize electrical connectors and the related need to reduce the size of each contact terminal, causes difficulty in forming the contact terminal as a cantilever beam spring which is strong enough to form a good contact.
Another technique used to create the contact force in electrical connectors uses a torsion bar. Torsion bar connector systems can generally be made smaller than cantilever beam spring systems and yet achieve relatively high contact forces. Known prior art torsion bar connector systems typically included a first contact terminal in the form of a rod which is inserted into a second contact terminal in the form of a helically-shaped sleeve. The rod acts as the spring portion to which torque is applied by the sleeve upon insertion to physically engage the rod with the sleeve. In current designs, however, the torque is also applied to the points at which the terminals are mounted, placing undesirable stress on the rod, sleeve and mounting points. Also, the current designs do not address the problem of high insertion forces in multi-terminal connectors.